Method and system for asset tracking in an enterprise environment

ABSTRACT

A method and system for tracking an asset in an indoor facility. The method includes receiving, from a first mobile device, an asset tracking tag collision report, the asset tracking tag collision report including a tag identifier of an asset tracking tag associated with an asset; determining a new location of the asset based on the received asset tracking tag collision report; updating an asset location database to indicate the new location of the asset; and, in response to determining the new location of the asset, transmitting an instruction message to a mobile device to cause the mobile device to direct the asset tracking tag to cease broadcasting the wireless signal. The method and system use crowd-sourcing to determine a new location of an asset that has moved in an indoor facility.

TECHNICAL FIELD

The present disclosure relates to asset tracking, and more particularly,to systems and methods for tracking locations of assets in an enterpriseenvironment.

BACKGROUND

Asset management is a key component of an enterprise environment. Achallenge in an enterprise environment is the tracking of physicallocations of assets, such as inventory and equipment, within theconfines of the enterprise's facilities. For example, in a companyoffice building or campus, assets may often be removed from or relocatedwithin the facility. Manual tracking of relocated assets in the facilityis generally a laborious process and can be a significant drain onworkplace productivity. On the other hand, installing complex andexpensive hardware for tracking assets may not be feasible orpractically desirable.

BRIEF DESCRIPTION OF THE DRAWINGS

Reference will now be made, by way of example, to the accompanyingdrawings which show example embodiments of the present application andin which:

FIG. 1 diagrammatically shows an asset tracking system for an indoorfacility in accordance with example embodiments of the presentdisclosure.

FIG. 2 shows, in flowchart form, an example method for tracking an assetin an indoor facility in accordance with example embodiments of thepresent disclosure.

FIG. 3 shows, in flowchart form, another example method for tracking anasset in an indoor facility in accordance with example embodiments ofthe present disclosure.

Like reference numerals are used in the drawings to denote like elementsand features.

DETAILED DESCRIPTION OF EXAMPLE EMBODIMENTS

The present application describes tracking the location of an asset inan indoor facility based on crowd-sourced data. A mobile device in anindoor facility may be used to detect a collision with a signalbroadcast by an asset tracking tag associated with an asset. Locationinformation associated with the mobile device at the time of detectingthe collision with the signal may be used to update an estimate of thephysical location of the asset. Crowd-sourced data from a plurality ofdevices may help to refine and improve the reliability of a lightweightasset tracking system for an indoor facility.

In one aspect, the present application describes a method implemented bya processor of a server for tracking an asset in an indoor facility. Themethod includes: receiving, from a first mobile device, an assettracking tag collision report, the asset tracking tag collision reportincluding a tag identifier of an asset tracking tag associated with theasset, wherein the tag identifier is transmitted to the first mobiledevice in a wireless signal broadcast by the asset tracking tag when theasset tracking tag determines that the asset has moved; determining anew location of the asset based on the received asset tracking tagcollision report; updating an asset location database to indicate thenew location of the asset; and, in response to determining the newlocation of the asset, transmitting an instruction message to a mobiledevice to cause the mobile device to direct the asset tracking tag tocease broadcasting the wireless signal.

In another aspect, the present application describes a system fortracking an asset in an indoor facility. The system includes: an assettracking tag associated with the asset, the asset tracking tag having atleast one sensor, wherein the asset tracking tag initiates broadcastinga wireless signal upon determining that the asset has moved; a firstmobile device configured to detect the wireless signal broadcast by theasset tracking tag; and a server connected to the first mobile device,wherein the server is configured to: receive, from the first mobiledevice, an asset tracking tag collision report, the asset tracking tagcollision report including a tag identifier of the asset tracking tag;and update an asset location database to indicate a new location of theasset based on the received asset tracking tag collision report.

Other example embodiments of the present disclosure will be apparent tothose of ordinary skill in the art from a review of the followingdetailed descriptions in conjunction with the drawings.

Modern mobile devices, such as cellular phones, are often equipped witha Global Positioning System (GPS) receiver chip and antenna which enablea mobile device to determine its location using broadcast signalsreceived from four or more satellites. While GPS functionalities inmobile devices may provide reasonably accurate location information whenthere is an unobstructed line of sight to four or more GPS satellites,GPS may not be suitable for use in an indoor setting, as signals fromsatellites may be attenuated and scattered by roofs, walls or otherinterior features.

Instead of relying on use of satellites, some systems employ radiofrequency identification (RFID) technologies for locating objects inGPS-denied environments such as office buildings. In such systems,wireless RFID tags may be connected to assets to assist in tracking thelocations of the assets within an indoor facility. These dedicatedtracking systems typically involve a plurality of RFID gateway readersand passive or active RFID tags connected to assets. The readerscontinuously monitor the locations of the assets by sending out triggeror polling signal to which the tags respond. These types of solutionsrequire costly dedicated infrastructure to be distributed throughout afacility and may require extensive maintenance.

In one aspect, the present application proposes an asset tracking systemthat uses crowd-sourcing to locate assets within an indoor facilityusing an indoor location system. In an enterprise environment, the datamay be obtained from devices associated with a plurality of employees ofthe enterprise. Rather than installing nodes/gateways at many pointsthroughout the facility or relying on transmissions from expensive,location-aware tags, the present system and method may collect locationdata associated with user devices, in their ordinary use within thefacility, that are in close proximity to one or more assets beingmonitored in order to approximate the locations of those assets.

System Overview

Reference is now made to FIG. 1, which diagrammatically shows an exampleembodiment of an asset tracking system 100 for an indoor facility 110.The asset tracking system 100 is connected to a network 10. The network10 may include one or more wired or wireless communication networks, orcombinations of both. For example, the network 10 may be a WirelessLocal Area Network (WLAN) that conforms to the IEEE 802.11 standards(sometimes referred to as Wi-Fi). The network 10 includes one or morewireless access points (APs) 30, such as Wi-Fi APs, which can transmitand receive radio frequencies for communication with wireless-enableddevices. The wireless APs 30 provide wireless connectivity to mobiledevices 20 and any computing devices within a local coverage area (suchas an indoor facility) that are equipped for wireless communicationusing a designated protocol, such as IEEE 802.11. In at least someembodiments, the wireless APs 30 are distributed throughout the facilityin known locations and each wireless AP 30 may be configured toperiodically broadcast an identifier unique to the AP 30.

The asset tracking system 100 includes one or more mobile devices 20. Inat least some embodiments, the mobile device 20 may be a communicationdevice such as a cellular phone. In the asset tracking system 100 ofFIG. 1, the mobile devices 20 are equipped for wireless communicationvia the wireless APs 30 and are capable of receiving broadcast messagesor signals output by the wireless APs 30. According to known techniques,a mobile device 20 can also measure the relative received signalstrength (RSSI) of detected signals from the wireless APs 30 as well asother sources of radio frequency transmission. An RSSI is a measurementof the power present in a received radio signal. The mobile devices 20may send and receive communication signals over the network 10 after therequired network registration or activation procedures have beencompleted. It will be appreciated that the asset tracking system 100 mayalso include one or more stationary electronic devices (not shown) suchas desktop computers or Voice over IP (VoIP) phones.

In at least some embodiments, the mobile devices 20 may be managed by aMobile Device Management (MDM) system. An MDM system includes a centralserver component, which administers and monitors the mobile devices 20,and a client component, which can be run on a mobile device 20 toreceive and execute management commands from the server component. TheMDM system enables an administration server to, among otherfunctionalities, configure and update device settings over-the-air,enforce security policies and compliance rules, and remotely deployapplications to end-users. Many MDM systems are implemented via devicemanagement software that can run on subscriber devices.

The mobile device 20 may include an asset tracking application 21. Theasset tracking application 21 detects wireless signals broadcast by anasset tracking tag 60 associated with an asset 50 in the indoor facility110. In at least some embodiments, the asset tracking application 21detects RSSI measurements for the wireless signals transmitted by assettracking tag 60.

In some embodiments, the mobile device 20 may include an indoorpositioning application 22. For example, in a network such as the WLANof FIG. 1, an indoor positioning application 22 may detect RSSImeasurements for wireless signals from a plurality of APs. The indoorpositioning application 22 can be configured to send the measured RSSIvalues to a remote server implementing an indoor positioning system. Theserver may then perform the computational work of correlating the RSSIvalues measured by the mobile device 20 with wireless AP fingerprintsthat are themselves correlated to a location in the indoor facility 110.In this manner, the indoor positioning application 22 may determine, forexample, the current location of the mobile device 20. In some otherembodiments, the indoor positioning application 22 may itself attempt tocorrelate measured RSSI values with wireless AP fingerprint data for theindoor facility 110, without transmitting the RSSI measurements to aremote server. The wireless AP measurements may be obtained from achipset, such as a Wi-Fi chip.

Other techniques for indoor navigation may be implemented by the indoorpositioning application 22. For example, sensor data may be collectedfrom a plurality of built-in sensors on the mobile device 20, such asaccelerometers, gyroscopes and/or magnetometers, and processed by theindoor positioning application 22 for implementing a sensor fusionalgorithm. As a further example, the indoor positioning application 22may be configured to measure a round-trip time (RTT) to a plurality ofwireless APs, based on signals exchanged with the APs, in order toestimate a current position of the mobile device 20. In at least someembodiments, the indoor positioning application 22 may use one or morehybrid algorithms for determining positions with the indoor facility110. In particular, a combination of techniques that exploit propertiesof wireless signals received from wireless APs may be implemented by theindoor positioning application 22. For example, a hybrid RSSI-RTTlocalization technique may be employed for tracking the location of themobile device 20.

The asset tracking application 21 and the indoor positioning application22 may be standalone applications or integrated with one another. Forexample, the indoor positioning application 22 may be integrated intothe asset tracking application 21, allowing a graphical map interfacemodule of the asset tracking application 21 to display the relativeposition of the mobile device 20 with respect to one or more trackedassets 50 within the indoor facility 110.

The mobile device 20 may include a short-range wireless communicationinterface which provides for communication between the mobile device 20and different systems or devices, which need not necessarily be similardevices. For example, the short-range communication interface mayinclude an infrared device and associated circuits and components, or aBluetooth® module to provide for communication with similarly-enabledsystems and devices.

The asset tracking system 100 includes a plurality of asset trackingtags 60 associated with tracked assets 50 within the indoor facility110. Assets may be shared between two or more employees or transferredfrom one employee to another employee in an enterprise. For example, asillustrated in FIG. 1, the asset 50 may be office equipment. Such assetsmay often be misplaced or not returned to their originating locationsafter use, or deliberately relocated to new locations within the indoorfacility 110. A task of the asset tracking system 100 is to attempt toestimate the location of the assets 50 to a reasonably high degree ofaccuracy.

The asset tracking tag 60 includes a housing 61 which provides a durablestructure to hold the components of the asset tracking tag 60. Thehousing 61 of the asset tracking tag 60 may be integral with the asset50 or may be secured to the asset 50 by affixing to an exterior surfaceof the asset 50. For example, the asset tracking tag 60 can be attachedto an asset 50 using an adhesive strip on at least one surface of thehousing 61 of the asset tracking tag 60.

The asset tracking tag 60 also includes a battery 62. The battery 62powers the components of the asset tracking tag 60. In at least someembodiments, the battery 62 is replaceable. The housing 61 of the assettracking tag 60 may include a built-in indicator providing visual orauditory indication of the charge state of the battery 62. For example,a light-emitting diode (LED) indicator may be turned on or set to blinkwhen the detected level of battery charge falls below a threshold value.

When the asset 50 is displaced from a resting position within the indoorfacility 110, the asset tracking tag 60 associated with the asset 50 canbe used for broadcasting a signal to indicate that the asset 50 iseither in motion or has come to a rest at a new location within thefacility. The asset tracking tag 60 may include at least one wirelesstransceiver 63 for transmitting wireless signals. A signal broadcast bythe asset tracking tag 60 may be received by one or more electronicdevices within a vicinity of the asset 50. In at least some embodiments,the wireless transceiver 63 may transmit signals using short-wavelengthultra-high frequency (UHF) radio waves. For example, the radio waves maybe in the Industrial, Scientific and Medical (ISM) 2.4 GHz short-rangeradio frequency band. In some embodiments, the wireless transceiver 63may be based on the Bluetooth® Low Energy (BTLE) specification, whichcan provide considerably reduced power consumption and cost compared toclassic Bluetooth® while maintaining a similar communication range. Itwill be appreciated that the asset tracking tag 60 may also oralternatively implement other types of short-range radio frequencycommunication protocols, such as near-field communication (NFC). Theasset tracking tag 60 is capable of sending data to and receiving datafrom those electronic devices in the indoor facility 110 that areequipped for wireless communication.

The asset tracking tag 60 may also include one or more sensors. In atleast some embodiments, the asset tracking tag 60 includes anaccelerometer 67. The accelerometer 67 is a device that generates anoutput signal in dependence on the acceleration of the accelerometer 67and specifies the magnitude and/or direction of acceleration. Theaccelerometer 67 may be integrated into the housing 61 of the assettracking tag 60 and generate accelerometer outputs based on movements ofthe asset tracking tag 60.

The accelerometer 67 defines one or more sensing axes. For example, theaccelerometer 67 may include three orthogonal sensing axes correspondingto the accelerometer's x sensing axis, y sensing axis and z sensingaxis. The accelerometer 67 may produce an accelerometer reading for eachof the sensing axes. For example, an accelerometer reading a_(x) may beproduced by the accelerometer 67 based on measurements associated withthe x sensing axis (such as an acceleration along the x sensing axis),an accelerometer reading a_(y) may be produced by the accelerometer 67based on measurements associated with the y sensing axis (such as anacceleration along the y sensing axis), and an accelerometer readinga_(z) may be produced by the accelerometer 67 based on measurementsassociated with the z sensing axis (such as an acceleration along the zsensing axis). These accelerometer readings may collectively form theaccelerometer output. In particular, the accelerometer output is anelectronic signal which represents the accelerometer readings a_(x),a_(y), a_(z) for each of the sensing axes of the accelerometer 67.

The asset tracking tag 60 may also include processing circuitry 64,memory 65 and a timer 66. The processing circuitry 64 may include anycombination of digital or analog circuitry for receiving signals fromthe accelerometer 67 and controlling operations of the transceiver 63 inaccordance with a desired protocol of operation. Example operations aredescribed below. In some embodiments, the processing circuitry 64 mayinclude discrete logic components, a field programmable gate array(FPGA), an application specific integrated circuit (ASIC), or otherdigital or analog circuitry.

The timer 66 may be a separate circuit element that is coupled to theprocessing circuitry 64 and is capable of providing a timestamp for anevent associated with the asset tracking tag 60. In some cases the timer66 is implemented by the processing circuitry 64 instead of being aseparate element. In at least some embodiments, the processing circuitry64 may be coupled to one or more of the wireless transceiver 63, theaccelerometer 67, the timer 66, the battery 62 and memory 65.

The asset tracking system 100 further includes a server 40 connected tothe network 10. The server 40 may be configured to determine thelocation information associated with one or more of the mobile devices20 and perform the computational work in estimating the locations ofassets 50 within the indoor facility 110. In at least some embodiments,the server 40 may be implemented as a collection of a plurality ofserver computers. The server 40 may include a memory 41, a processingunit 42 and a communication subsystem 43. In some embodiments, thememory 41 may store device information for one or more of the mobiledevices 20 and their associated locations within the indoor facility110. For example, the memory 41 may contain a database of managed mobiledevices 20 in the indoor facility 110. For a managed mobile device 20,the database may indicate one or more of: a device identifier (e.g.serial number, phone number), a user associated with the device 20,history of visited locations in the indoor facility 110 (includingappropriate timestamps) and a current location of the device 20. Thememory 41 may optionally store map data identifying the currentlocations of the managed mobile devices 20. In some cases, the server 40may not have device information for the mobile devices 20 in the indoorfacility 110. In other words, when a mobile device 20 in the indoorfacility 110 detects a wireless signal from an asset tracking tag 60,the mobile device 20 may be configured to establish a connection to theserver 40 for the first time and transmit device information for themobile device 20 to the server 40 for processing by the server 40.

The server 40 of the asset tracking system 100 has access to an assetlocation database 45. For example, the asset location database 45 may bestored in the memory 41 or remotely accessed by the server 40 forretrieving and updating location data associated with the assets 50. Inat least some embodiments, the asset location database 45 keeps track ofthe locations of assets 50 as well as other useful informationpertaining to the assets 50 and their associated asset tracking tags 60.For example, the asset location database 45 may contain data related toa tracked asset 50 including, but not limited to: asset identifier;identifier of associated asset tracking tag; history of locations withinthe facility 110 and relevant timestamps; a current location of theasset; identifiers of devices that reported detected signals from theassociated asset tracking tag; first date of tracking; last date oflocation update; asset-user associations; and last date of change ofbattery of the associated asset tracking tag. In some embodiments, theasset location database 45 may include a graphical map interface modulefor displaying the current locations of tracked assets 50.

The processing unit 42 may include a single processor with multiplecores or multiple processors (with single or multiple cores). Theprocessing unit 42 interacts with the communication subsystem 43 toperform communication functions via the network 10 with other systems,servers and/or devices such as the mobile devices 20.

In at least some embodiments, the server 40 may have access to orimplement an indoor positioning system for the facility 110. The server40 may connect to and retrieve location data for mobile devices 20 froman indoor positioning system. The indoor positioning system may, forexample, be a system based on wireless AP fingerprints within thefacility 110. The server 40 may itself implement the indoor positioningsystem or request location data associated with one or more mobiledevices 20 from a separate indoor positioning system. That is, thelocation associated with a mobile device 20 in the facility 110 may bedetermined directly by the server 40 or a separate system to which theserver 40 has access for sending and retrieving data.

Reference is now made to FIG. 2, which shows, in flowchart form, oneexample process 200 for tracking the location of an asset in an indoorfacility using crowd-sourced data. The process 200 may be implemented byan asset tracking system such as the asset tracking system 100 shown inFIG. 1.

In operation 202, an asset tracking tag associated with a tracked assetdetects that the asset has moved. When an asset is moved (e.g. carried)from a first location to a second location within a facility, the assetand its associated asset tracking tag may experience motion. In thiscase, a processing circuitry of the asset tracking tag may receivesensor data from one or more sensors contained in the asset tracking tagindicating that the associated asset has undergone movement. Forexample, an accelerometer associated with the asset tracking tag maydetect an acceleration (e.g. a movement about a z sensing axis of theaccelerometer) as well as a duration of the experienced acceleration.

In its default state, the processing circuitry of the asset tracking tagmay be in a “sleep” mode, drawing little or no battery power. Theaccelerometer of the asset tracking tag may remain in a low-power, idlestate. When a change in motion of the asset tracking tag is detected,the accelerometer is configured to signal the processing circuitry towake up. Other mechanisms for preserving the battery level whilemonitoring the motion of the asset tracking tag may be available in someembodiments.

In order to determine whether the asset has moved from a first location,one or more thresholds may be established for comparing receivedaccelerometer readings from the accelerometer of the asset tracking tag.In particular, outputs from the accelerometer of the asset tracking tagmay be compared against threshold values. For example, if anaccelerometer output exceeds a first pre-determined threshold value, theprocessing circuitry of the asset tracking tag may determine that theasset is experiencing motion. By way of further example, if theaccelerometer readings, after accounting for possible bias, indicate anon-zero output for a duration longer than a pre-determined timeinterval, the processing circuitry of the asset tracking tag maydetermine that the asset is being moved. In some embodiments, athreshold value may be defined for each of the sensing axes of theaccelerometer. If the accelerometer detects that output for one or moreof the sensing axes is greater than the threshold value for therespective axis, the processing circuitry of the asset tracking tag mayconclude that the asset is moving.

Once the processing circuitry of the asset tracking tag determines thatthe asset has moved, in operation 204, the processing circuitry maycause one or more wireless transceivers of the asset tracking tag tostart broadcasting a wireless beacon signal. The wireless transceivermay initiate broadcasting the signal upon first detecting movement (e.g.when accelerometer output exceeds a first threshold value) or when theprocessing circuitry determines that the asset has relocated and isresting at a new location (e.g. zero acceleration after a period ofmovement). If the wireless transceiver start to broadcast the signal atthe first sign of motion, the signalling may continue throughout theduration of travel of the asset and after the asset has come to a restor may continue until a maximum time is reached. If the maximum time isreached and the asset is still undergoing movement, then thebroadcasting may cease until the asset is at rest again so as to avoiddraining the battery during lengthy travel (e.g. during shipping).

In at least some embodiments, the wireless transceiver of the assettracking tag may broadcast a signal when the asset is first deployed inthe indoor facility. In particular, the asset tracking tag may beaffixed to the asset at the time of deploying the asset. Broadcasting bythe asset tracking tag upon first deployment of the asset may allow theasset to be tracked from the start of its deployment within the indoorfacility and facilitate the server's determination of an initiallocation of the asset. In some other embodiments, a wireless signal maybe broadcast when the asset tracking tag first becomes operational. Forexample, if the asset tracking tag is attached to the asset after theasset has already been deployed in the indoor facility, when the assettracking tag is first activated, either manually or by registering witha remote server, the processing circuitry may cause a wireless beaconsignal to be broadcast.

The signal broadcast by the asset tracking tag may include differenttypes of data. The signal may represent data about the asset trackingtag, including, without limitation: unique identifier; product ormanufacturer code; identifier of the associated asset; current batterystatus; time of detection of motion; state of motion (i.e. whether theasset is in motion or has come to a rest); and time of transmission ofwireless signal. In some embodiments, the broadcast signal may representother information associated with the asset or the asset tracking tag.For example, the signal may indicate that there is a problem with theasset (e.g. asset is being removed from a designated space) or the assettracking tag (e.g. tag is malfunctioning).

In at least some embodiments, transmission of the broadcast signal mayoccur continuously at a pre-determined rate. In particular, theprocessing circuitry of the asset tracking tag may be programmed toestablish a fixed transmission rate for the broadcast signal and tocontrol the wireless transceiver to broadcast at the fixed rate.

In some embodiments, the transmission rate may be variable. For example,the transmission rate may depend, in part, on the remaining charge forthe battery associated with the asset tracking tag. If the remainingcharge of the battery falls below a threshold level, the transmissionrate of the broadcast signal may be decreased. As a further example, thetransmission rate may depend on the motion status of the asset trackingtag. In particular, the transmission rate may be different according towhether the asset is currently in motion or at rest at a new location.The asset tracking tag may determine its motion status based on sensordata and adjust the transmission rate according to the motion status.For example, the transmission rate may be higher when the asset is atrest. Other conditions may be used to vary the transmission rate of thebroadcast signal from the asset tracking tag. In some embodiments, thetransmission of the wireless signal may switch between a fixed rate anda variable rate. The asset tracking tag may continue to broadcast thesignal until an explicit instruction is received to cease transmissionof the signal. A degree of randomness in the frequency of broadcasts maybe employed for collision avoidance in some embodiments.

In operation 206, a mobile device that is within range of the signalbroadcast by the asset tracking tag detects the signal. It will beappreciated that both stationary (i.e. at-rest) and moving/travellingdevices within the indoor facility may be capable of detecting thebroadcast signal from the asset tracking tag, either during movement ofthe asset to a new location or after the asset has come to a rest at thenew location, or both.

Upon detecting the broadcast signal from the asset tracking tag, themobile device may generate an asset tracking tag collision report. Anasset tracking tag collision report specifies an identifier of the assettracking tag associated with the tracked asset. It will be appreciatedthat a device may detect a plurality of broadcast signals transmitted bythe asset tracking tag. As such, the asset tracking tag collision reportmay include a timestamp associated with each of a plurality of signalsreceived from the asset tracking tag. The asset tracking tag collisionreport may also include an RSSI associated with each of the receivedsignals. In some embodiments, the mobile device may generate one assettracking tag collision report for each received broadcast signal fromthe asset tracking tag. In particular, each time a broadcast signal isdetected, the device may generate an asset tracking tag collisionreport, indicating, at least, a timestamp and an RSSI associated withthat signal. In some other embodiments, the mobile device may generateone asset tracking tag collision report containing data for a pluralityof received broadcast signals. The asset tracking tag collision reportmay also include an identifier of the mobile device that generated thereport.

In at least some embodiments, the asset tracking tag collision reportmay specify a location of the mobile device associated with a time atwhich a broadcast signal from the asset tracking tag is received by themobile device. That is, the asset tracking tag collision report mayidentify a location within the facility at the time when the mobiledevice detected a broadcast signal transmitted by the asset trackingtag. For example, when a broadcast signal is detected, an indoorpositioning application on the mobile device may be used to identify alocation of the mobile device associated with the timestamp for thedetection of the broadcast signal. Where an asset tracking tag collisionreport includes data for multiple received broadcast signals, the reportmay indicate a location of the mobile device associated with each of thereceived signals. In some embodiments, the asset tracking tag collisionreport may include data that can be used by an indoor positioning systemto determine a location of the mobile device within the facility at thetime when the mobile device detected a broadcast signal from the assettracking tag, without expressly indicating a specific location of themobile device within the facility. For example, the asset tracking tagcollision report may include RSSI measurements for wireless signalsreceived from a plurality of APs, which measurements can be used by anindoor positioning system to identify a specific location in thefacility.

In operation 208, the mobile device transmits the generated assettracking tag collision report to a server. In at least some embodiments,the mobile device may transmit an asset tracking tag collision report tothe server each time a broadcast signal is detected from the assettracking tag. In other embodiments, the mobile device may generate oneasset tracking tag collision report based on data from multiple receivedsignals and transmit the report to the server.

A server receiving a plurality of asset tracking tag collision reportsmay be able to determine an updated location of a tracked asset based ondata from the reports. The server may receive asset tracking tagcollision reports from a plurality of devices which encounter broadcastsignals from the asset tracking tag associated with the tracked asset.The server may also receive multiple asset tracking tag collisionreports from a single device that detects broadcast signals from theasset tracking tag. In at least some embodiments, the server maydetermine the location of a device that transmits an asset tracking tagcollision report. For example, if an asset tracking tag collision reportincludes an identifier of the mobile device that generated andtransmitted the report, the server may use an indoor positioning systemfor the facility to determine the location of the mobile device based onthe identifier. In some other embodiments, an asset tracking tagcollision report may itself indicate the location of the mobile devicethat transmitted the report.

The server maintains a collisions history record of all asset trackingtag collision reports received from the mobile devices in the facility.For example, the entries in the collisions history record may beorganized by timestamps associated with received signals (e.g. time oftransmission of broadcast signal by asset tracking tag) as indicated inthe asset tracking tag collision reports. In particular, for each time,the collisions history record may specify the identities of the mobiledevices that detected a signal broadcast by the asset tracking tag aswell as other relevant information about the respective received signal(e.g. RSSI). Where an asset tracking tag collision report includes thelocation of the mobile device that generated and transmitted the report,the collisions history record maintained by the server will also specifythe location of the mobile device in association with the time at whichthe mobile device detected a broadcast signal from the asset trackingtag. Based on this crowd-sourced approach, the server may be able tocollect sufficient amount of data from the asset tracking tag collisionreports to develop and refine an estimate of a new location of the assetwithin the facility. That is, a determination of the new location of theasset includes obtaining an estimate of the new location based on datafrom the asset tracking tag collision reports.

One technique for deriving an estimate of the asset's location istrilateration. Given two independent measurements of distance from theasset to mobile devices with known locations, the location of the assetcan be narrowed to two possibilities, and any additional information(e.g. a third distance measurement to a third mobile device with a knownlocation) may uniquely identify the asset's location. In someembodiments, the system may use one or more signal parameters to assistin location determination. For example, an RSSI for the signal broadcastby the tag may be used to determine an estimated distance to a receiverfrom the source of the signal. While accurate distances may generallynot be obtained using signal parameters alone, several indoorlocalization systems based on signal parameters have been successfullyimplemented. Such systems are described in, at least, “An indoorbluetooth-based positioning system: Concept, implementation andexperimental evaluation.” (Silke Feldmann, Kyandoghere Kyamakya, AnaZapater, and Zighuo Lue. International Conference on Wireless Networks,pages 109-113, 2003), “Indoor localization using Bluetooth.” (TiagoFernandes, 6th Doctoral Symposium in Informatics Engineering, pages480-483, 2011), both of which are incorporated herein by reference. Asimplified distance estimation model is given in “Accuracy of LocationIdentification with Antenna Polarization on RSSI” (Xu Huang, MarkBarralet, Dharmendra Sharma. Proceedings of the InternationalMulti-Conference of Engineers and Computer Scientists, 2009) by equation(1):RSSI=−(10×n)log₁₀d−A  (1)where RSSI is measured in dBm, n represents a path loss exponent (whichdepends on the propagation characteristics of the received signal), d isdistance in meters between a transmitter and a receiver and A is areference RSSI at a distance of 1 meter from the transmitter. In orderto use equation (1), the values of n and A may be determinedempirically. Other localization algorithms using trilateration may beused by the server to develop an estimate of the location of an assetbased on data from a plurality of (i.e. at least three) asset trackingtag collision reports.

With each receipt of an asset tracking tag collision report, the servermay use the additional data from the report to refine the computation ofan estimate of the asset's location. In at least some embodiments, theserver may include an asset location estimation module that isconfigured to apply a suitable localization algorithm to data from aplurality of received asset tracking tag collision reports. For aspecific timestamp in the collisions history record maintained by theserver, the server may use the one or more entries corresponding to thetimestamp to determine the location of a mobile device that detected abroadcast signal from the asset tracking tag and an RSSI of the detectedbroadcast signal. The server may extract the location information of themobile device from the asset tracking tag collision report itself oraccess an indoor positioning system for the facility in order toidentify a location corresponding to the mobile device using thedevice's identifier (specified in the asset tracking tag collisionreport). For example, if the asset tracking tag collision reportincludes RSSI measurements for wireless signals received by the mobiledevice from a plurality of APs within the facility, the indoorpositioning system may correlate the RSSI measurements with wireless APfingerprints for the facility in order to determine the location of themobile device. The location of the mobile device and the RSSI of thebroadcast signal from the asset tracking tag that the device detects canbe input to the asset location estimation module to generate an updatedestimate of the new location of the asset at the relevant time.

In some cases, the server may not have sufficient data for atrilateration-based localization technique. For example, the server mayreceive no more than two asset tracking tag collision reports frommobile devices in the facility. In such cases, the server may beconfigured to collect context data about the tracked asset or thefacility to determine an estimated location of the asset. For example,if the server only receives location data from two mobile devicesdetecting a broadcast signal, reducing the number of possible locationsof the asset to two, the server may access an indoor positioning systemfor the facility and determine that one of the possibilities is aninaccessible location, thus eliminating the possibility as a viablelocation for the asset. As a further example, if the tracked asset isequipment for a presentation (e.g. projector screen, audiovisualequipment), the server may determine that the asset is not likely to belocated in a washroom or kitchen area. In at least some embodiments, theserver may extrapolate a location of an asset by forming a trajectory ofthe asset's traveled path or by using a dead reckoning technique.

It will be appreciated that, in an indoor facility, room-levellocalization is often sufficient for locating assets that are beingtracked, and so a highly accurate measurement of distances may not berequired. For example, if office equipment, such as a printer, faxmachine or hole-punch, can be traced to a single room within a facility,it may be a simple process to locate the equipment inside the room.

In operation 210, the server updates an asset location database toindicate the new location of the asset. The asset location database maybe stored in a memory associated with the server or stored at a remotelocation accessible by the server. In at least some embodiments, theasset location database may identify two variables, namely, “estimate ofthe new location of the asset” and “final determined new location of theasset”. As the server receives an asset tracking tag collision reportfrom a mobile device and refines an estimate of the asset's locationbased on the data from the report, the server will update the “estimateof the new location of the asset” variable. When the server determines,to a desired degree of confidence, the new location of the asset, the“final determined new location of the asset” variable can be set to themost recent value of the “estimate of the new location of the asset”variable.

In formulating estimates of the location of the asset based on data froma plurality of asset tracking tag collision reports, the server may beconfigured to apply suitable weightings to signal measurement data. Inparticular, in a triangulation-based localization algorithm, the servermay place greater weight on the locations of some mobile devices thanthe locations of other mobile devices. For example, if a particularmobile device receives multiple signals from the asset tracking tag, thelocation(s) of that mobile device may be accorded more weight in alocalization algorithm than another mobile device which reports only asingle detected signal. By way of further example, if a mobile devicereports a high magnitude RSSI for a received signal, greater weight maybe placed on the location(s) of that mobile device than other mobiledevices. Other criteria for distribution of weights to the locations ofdifferent mobile devices in the server's localization algorithm may beavailable.

In at least some embodiments, the server may perform a check todetermine whether an estimate of the new location of the asset satisfiesa pre-determined confidence threshold. For example, after the serverupdates the “estimate of the new location of the asset” variable at theasset location database based on data from an asset tracking tagcollision report, the server may verify, in real-time, whether thecurrent value of the “estimate of the new location of the asset”variable satisfies a confidence threshold.

Various confidence thresholds may be appropriate for estimating thelocation of an asset. For example, the confidence threshold may besatisfied if more than a threshold number of asset tracking tagcollision reports from different mobile devices is received by theserver for a certain time. As a further example, if more than athreshold number of signals is received by a single mobile device, themobile device may correspond to a user who is physically moving theasset, suggesting that an estimate of the asset's location based on thelocation of the user's mobile device is likely to be accurate. Theserver may also consider other factors in determining that an estimateof the asset's location is confidently correlated to its actuallocation, including the state of motion of the asset (i.e. whether theasset is in motion or at rest) and magnitude of RSSI of receivedsignals. In at least some embodiments, a memory associated with theserver may store one or more pre-determined rules regarding confidencethresholds for estimates of an asset's location.

If the server determines that a confidence threshold is satisfied, theserver may select a device in the facility and instruct the device tocause the asset tracking tag associated with the tracked asset to ceasebroadcasting its wireless signal. When it is determined that a server'sestimate of the asset's location is accurate to a desired degree, theasset tracking tag can be alerted so that signal transmission can behalted, preventing any unnecessary power consumption by the assettracking tag. In at least some embodiments, the server selects a device(either stationary or mobile) that is determined to be located close tothe estimated location of the asset. The device that is selected may beone of the devices that transmitted an asset tracking tag collisionreport to the server. The selected device may also be a device that ismanaged by the server or a device whose location is known to the serverand is communicably connected to the server. If the server is unable tocommunicate an instruction message to a selected device, a differentdevice may be selected. The order of selection of devices may be based,at least in part, on proximity of the devices to the estimated locationof the asset. In some embodiments, a confidence threshold does not needto be satisfied for the server to direct a mobile device to cause theasset tracking tag to stop transmitting its signal.

In some embodiments, if the server determines that an estimate of thenew location of an asset satisfies a confidence threshold, the servermay instruct a plurality of devices in the facility to instruct theasset tracking tack to cease broadcasting Rather than selecting a singledevice for the task of shutting off the signal broadcasting by the assettracking tag, the server may instruct a plurality of devices to listenfor the asset tracking tag so that further broadcasting can beprevented. When a first one of the plurality of devices detects theasset tracking tag (e.g. detects a signal broadcast by the assettracking tag), the mobile device may then transmit an instruction to theasset tracking tag to cease broadcasting its signal. In someembodiments, the mobile device may also notify the server thatbroadcasting by the asset tracking tag has been discontinued. Uponreceiving a confirmation from the mobile device that the broadcasting ofthe asset tracking tag has been halted, the server may advise the otherdevices in the plurality of devices that they need not look for thatasset tracking tag any longer. This “cancellation” instruction preventsthe devices from later inadvertently turning off the asset tracking tagif it is moved again and begins rebroadcasting.

Reference is now made to FIG. 3, which shows, in flowchart form, aserver-implemented method for tracking an asset in an indoor facility.In at least some embodiments, the process 300 may be implemented by aserver such as the server 40 of FIG. 1. By way of example, the process300 may be implemented by a Mobile Device Management server whichmanages a plurality of the mobile devices 20 in the indoor facility 110(shown in FIG. 1). The server is communicably connected to the mobiledevices in the indoor facility via a wireless network, such as a WLAN.

In operation 302, the server receives an asset tracking tag collisionreport from a mobile device in the indoor facility. An asset trackingtag initiates broadcast of a wireless signal upon detecting that theasset with which it is associated is moving or has moved to a differentlocation in the facility. The wireless signal may be broadcastcontinuously by the asset tracking tag at a pre-determined fixedtransmission rate or at a variable rate. When a mobile device moves intorange of the broadcast signal, the mobile device detects an RSSI of thereceived signal and receives data represented in the signal. Forexample, the mobile device may receive, at least, a tag identifier forthe asset tracking tag that broadcast the signal.

The mobile device may be configured to generate and send an assettracking tag collision report on detecting a broadcast signal from theasset tracking tag. An asset tracking tag collision report includesinformation, provided by a mobile device in the facility, which mayassist the server to determine an approximate location of a trackedasset. In at least some embodiments, the asset tracking tag collisionreport may specify, at least, a tag identifier of the asset tracking tagassociated with the tracked asset, an identifier of the mobile devicewhich detected the broadcast signal, an RSSI of the signal received bythe mobile device, and a timestamp associated with the signal detectionevent.

The mobile device may send an asset tracking tag collision report to theserver each time a broadcast signal is detected by the mobile device.Alternatively, the mobile device may collect and store signalmeasurement data in a memory associated with the mobile device andgenerate a single asset tracking tag collision report for a plurality ofsignal detection events. For example, the mobile device may send oneasset tracking tag collision report to the server, providing theassociated timestamp and RSSI measurement data for each broadcast signalreceived from the asset tracking tag.

When the server receives an asset tracking tag collision report from amobile device, the server determines a location associated with themobile device within the indoor facility for each signal detection eventincluded in the asset tracking tag collision report. In particular, theserver determines the locations where the mobile device detectedbroadcast signals. In at least some embodiments, for each signaldetection event, the server may access an indoor positioning system forthe indoor facility and use the identifying information for the mobiledevice to determine a location of the mobile device at the time that thesignal was detected. In some other embodiments, the mobile device mayitself determine its location for each signal detection event andindicate, in the asset tracking tag collision report, the locationcorresponding to the timestamp for the signal detection event. Forexample, the mobile device may request its location from an on-boardindoor positioning application when a broadcast signal is detected fromthe asset tracking tag and store this location information with theassociated timestamp for the detected signal in memory.

By collecting data from a plurality of asset tracking tag collisionreports associated with an asset tracking tag, the server can maintain arecord of all signal detection events for the asset tracking tag. Basedon the record of signal detection events, the server can obtainestimates of the location of the asset tracking tag and the associatedasset. For example, if the server has location information for three ormore devices that each detected a broadcast signal from the assettracking tag at a given time (or a range of time) and the signalstrength information (i.e. RSSI) of the signal detected by therespective devices, the server can perform trilateration to determine anestimate of the location of the asset tracking tag at the given time (orrange of time). Using a crowd-sourced approach, the server can receiveasset tracking tag collision reports from a plurality of mobile devicesor a plurality of asset tracking tag collision reports from a singledevice to develop and refine an estimate of the tracked asset's locationwithin the facility.

In operation 306, the server updates an asset location database toindicate a new location of the tracked asset. The server can update theasset location database when a final estimate of the asset's location isdetermined or the server can update the asset location database on amore frequent basis. For example, the server may update the databaseeach time that an estimate of the asset's location is updated using datafrom a signal detection event.

In operation 308, the server transmits an instruction to one or moremobile devices within the facility to cause the mobile device(s) todirect the asset tracking tag to cease broadcasting its signal. That is,the server can control when and how to shut off the signal broadcastingfrom the asset tracking tag. For example, when the server determinesthat the estimate of the new location of the asset has been ascertainedto a desired degree of accuracy, the server may instruct one or moremanaged mobile devices to direct the asset tracking tag to stopbroadcasting. The asset tracking tag will start broadcasting again upondetermining that the associated asset is moving or has been moved again.

Where the server has access to an indoor positioning system for thefacility, the server can select a device that is known to be close tothe estimated new location of the asset for the task of directing theasset tracking tag to shut off the signal broadcasting. In someembodiments, the selected device may be a mobile device that transmittedan asset tracking tag collision report to the server. In otherembodiments, the selected device may be any electronic device that islocated in the vicinity of the asset's estimated new location. Forexample, the selected device may be a Bluetooth®-enabled device locatedin a room determined to be the room to which the asset has beenrelocated.

The various embodiments presented above are merely examples and are inno way meant to limit the scope of this application. Variations of theinnovations described herein will be apparent to persons of ordinaryskill in the art, such variations being within the intended scope of thepresent application. In particular, features from one or more of theabove-described example embodiments may be selected to createalternative example embodiments including a sub-combination of featureswhich may not be explicitly described above. In addition, features fromone or more of the above-described example embodiments may be selectedand combined to create alternative example embodiments including acombination of features which may not be explicitly described above.Features suitable for such combinations and sub-combinations would bereadily apparent to persons skilled in the art upon review of thepresent application as a whole. The subject matter described herein andin the recited claims intends to cover and embrace all suitable changesin technology.

The invention claimed is:
 1. A server-implemented method for tracking anasset in an indoor facility, comprising: receiving, from a first mobiledevice connected to the server via a wireless communication network, anasset tracking tag collision report, the asset tracking tag collisionreport including a tag identifier of an asset tracking tag associatedwith the asset, wherein the tag identifier is transmitted to the firstmobile device in a wireless signal broadcast by the asset tracking tagwhen the asset tracking tag determines that the asset has moved;determining a new location of the asset based on the received assettracking tag collision report; updating an asset location database toindicate the new location of the asset; and in response to determiningthe new location of the asset, transmitting an instruction message to amobile device to cause the mobile device to direct the asset trackingtag to cease broadcasting the wireless signal, wherein transmitting theinstruction message to the mobile device comprises transmitting theinstruction message to a plurality of mobile devices within thefacility, whereby the next of the plurality of mobile devices to detectthe wireless signal from the asset tracking tag will instruct the tag tocease broadcasting.
 2. The method of claim 1, wherein the asset trackingtag collision report contains location information regarding thelocation of the first mobile device within the indoor facility at thetime when the wireless signal was detected by the first mobile device.3. The method of claim 2, wherein the location information identifies alocation within the facility determined by the mobile device using anindoor positioning application.
 4. The method of claim 2, wherein thelocation information includes wireless access point signal measurementsfrom the mobile device and wherein the method further comprisesdetermining a location of the mobile device based on the wireless accesspoint signal measurements using an indoor positioning system.
 5. Themethod of claim 1, wherein the asset tracking tag collision reportfurther includes a received signal strength indicator (RSSI) of thewireless signal detected by the first mobile device.
 6. The method ofclaim 1, wherein determining the new location of the asset based on thereceived asset tracking tag collision report comprises determiningwhether the new location of the asset meets a predetermined confidencethreshold.
 7. The method of claim 1, wherein the asset tracking tag isaffixed to or integral with the asset.
 8. The method of claim 1, whereinthe asset tracking tag determines that the asset has moved based onsensor data received from at least one sensor associated with the assettracking tag.
 9. The method of claim 8, wherein the at least one sensorcomprises an accelerometer.
 10. The method of claim 1, furthercomprising maintaining a record of asset tracking tag collision reportsfor the asset received from a plurality of mobile devices.
 11. Themethod of claim 10, wherein determining the new location of the assetcomprises obtaining an estimate of the new location of the asset by atrilateration method based on data from the asset tracking tag collisionreports received from the plurality of mobile devices.
 12. A system fortracking an asset in an indoor facility, comprising: an asset trackingtag associated with the asset, the asset tracking tag having at leastone sensor, wherein the asset tracking tag broadcasts a wireless signalupon determining that the asset has moved; a first mobile deviceconfigured to detect the wireless signal broadcast by the asset trackingtag; and a server connected to the first mobile device via a wirelesscommunication network, wherein the server is configured to: receive,from the first mobile device, an asset tracking tag collision report,the asset tracking tag collision report including a tag identifier ofthe asset tracking tag; determine a new location of the asset based onthe received asset tracking tag collision report; update an assetlocation database to indicate the new location of the asset; andtransmit an instruction message to a mobile device to cause the mobiledevice to direct the asset tracking tag to cease broadcasting thewireless signal, wherein transmitting the instruction message to themobile device comprises transmitting the instruction message to aplurality of mobile devices within the facility, whereby the next of theplurality of mobile devices to detect the wireless signal from the assettracking tag will instruct the tag to cease broadcasting.
 13. The systemof claim 12, wherein the server is further configured to determine alocation of the first mobile device within the indoor facility at thetime when the wireless signal was detected by the first mobile device.14. The system of claim 12, wherein the asset tracking tag collisionreport further includes a received signal strength indicator (RSSI) ofthe wireless signal detected by the first mobile device.
 15. The systemof claim 12, wherein the server is further configured to: determine thatthe new location of the asset meets a predetermined confidencethreshold; and in response to determining that the new location of theasset meets the predetermined confidence threshold, transmit aninstruction message to a mobile device to cause the mobile device todirect the asset tracking tag to cease broadcasting the wireless signal.16. The system of claim 12, wherein the asset tracking tag determinesthat the asset has moved based on output data received from anaccelerometer.
 17. The system of claim 12, wherein the server is furtherconfigured to maintain a record of asset tracking tag collision reportsfor the asset received from a plurality of mobile devices.
 18. Thesystem of claim 17, wherein determining the new location of the assetcomprises obtaining an estimate of the new location by a trilaterationmethod based on data from the asset tracking tag collision reportsreceived from the plurality of mobile devices.
 19. The system of claim12, wherein the asset tracking tag broadcasts a wireless signal upondetermining that the asset has been deployed for the first time.
 20. Anon-transitory computer-readable medium storing processor-executableinstructions for a server to track an asset in an indoor facility,wherein the instructions comprise: instructions to receive, from a firstmobile device connected to the server via a wireless communicationnetwork, an asset tracking tag collision report, the asset tracking tagcollision report including a tag identifier of an asset tracking tagassociated with the asset, wherein the tag identifier is transmitted tothe first mobile device in a wireless signal broadcast by the assettracking tag when the asset tracking tag determines that the asset hasmoved; instructions to determine a new location of the asset based onthe received asset tracking tag collision report; instructions to updatean asset location database to indicate the new location of the asset;and instructions to transmit, in response to determining the newlocation of the asset, an instruction message to a mobile device tocause the mobile device to direct the asset tracking tag to ceasebroadcasting the wireless signal, wherein transmitting the instructionmessage to the mobile device comprises transmitting the instructionmessage to a plurality of mobile devices within the facility, wherebythe next of the plurality of mobile devices to detect the wirelesssignal from the asset tracking tag will instruct the tag to ceasebroadcasting.